Writing a blameless postmortem

The sections

1. Summary: two sentences a customer could read.
2. Impact: who was affected, for how long, how badly.
3. Timeline: times in one time zone, from first signal to resolved.
4. Cause: the chain of conditions, not a person.
5. What went well: keep doing these.
6. What to change: each item with an owner and a date.

Blameless, concretely

Write "the deploy had no check for the missing variable", not "Sam forgot the variable". The first leads to a fix; the second leads to people hiding mistakes.

Generate a filled-in draft with the postmortem template tool.

Updated October 22, 2026.